Preparation of white oils with aluminum-alkyl activated iron group metal catalysts

ABSTRACT

A process for upgrading and improving the color, odor and stability of petroleum oils to render the latter suitable for use in specialty applications. Raw distillates and semi-refined oils of suitable boiling range and viscosity are refined, or further refined, in a hydrogenation process, at suitable conditions, in the presence of a catalyst which comprises a support and a transition metal complexed with an organometallic compound, to yield colorless mineral oils, i.e., white oils. These highly refined oils are used in pharmaceuticals and cosmetics and similar compositions requiring oil components that meet certain high quality standards.

United States Patent Gilbert et a1. I

1451 1 Apr. 25, 1972 PREPARATION OF WHITE OILS WITH ALUMINUM-ALKYLACTIVATED IRON GROUP METAL CATALYSTS John B. Gllbert; Robert Kartzmark,both 'of Sarnia, Ontario, Canada Inventors:

Esso Research and Engineering Company, Linden, NJ.

Filed: Oct. 28, 1969 Appl. No.: 871,943

Assignee:

US. Cl ..208/89, 208/210, 208/211,

2,946,743 7/1960 Moy et a1 ..208/217 3,392,112 7/1968 Bercik et al..

3,412,174 10/1968 Kroll ..208/143 3,414,506 12/1968 Van LookerenCampagne.....208/264 3,340,181 9/1967 Diringer et a1 ..208/21 1 PrimaryExaminer-Delbert E. Gantz Assistant Examiner-G. J. CrasanakisAttorney-Pearlman and Stahl and Llewellyn A. Proctor 5 7] ABSTRACT Aprocess for upgrading and improving the color, odor and stability ofpetroleum oils to render the latter suitable for use in specialtyapplications. Raw distillates and semi-refined oils of suitable boilingrange and viscosity are refined, or further refined, in a hydrogenationprocess, at suitable conditions, in the presence of a catalyst whichcomprises a support and a transition metal complexed with anorganometallic compound, to yield colorless mineral oils, i.e., whiteoils. These highly refined oils are used in pharmaceuticals andcosmetics and similar compositions requiring oil components that meetcertain high quality standards.

13 Claims, No Drawings PREPARATION OF WHITE OILS WITH ALUMINUM- ALKYLACTIVATED IRON GROUP METAL CATALYSTS White oils are highly refined oilsderived from petroleum which have been extensively treated to virtuallyeliminate oxygen, nitrogen, sulfur compounds and reactive hydrocarbonssuch as aromatic hydrocarbons. White oils fall into two classes, i.e.,technical white oils which are used in cosmetics, textile lubrication,insecticide base oils, etc., and the even more highly refinedpharmaceutical white oils which are used in drug compositions, foods andfor the lubrication of food handling machinery. For all of theseapplications white oils must be chemically inert and without color, odorand taste.

The conventional method of making white oils involves refining petroleumoils with sulfuric acid. The acid removes impurities and reactivecompounds by chemical reaction and by solvation. Acid treating is costlybecause it results in low product yields and produces large amounts ofsludge and spent acid which must be disposed of, along with spent clayused for treatment of the product to remove traces of sulfonates and thelike.

It is known to produce semi-refined oils by extraction methods, withsubsequent hydrogenation of the raffinates, though the high qualitystandards required of white oils cannot be met by such techniques. It isthus known that selected oils can be extracted with solvents to obtain araffinate low in aromatics, and that the raffinate can be subjected tohydrogenation in the presence of an active hydrodesulfurization catalystto saturate or destroy heterocyclic compounds containing sulfur,nitrogen and oxygen to produce a semi-refined oil, or oil whichapproaches but does not meet white oil specifications. White oilspecifications are rather difficult to meet, for such oils must have acolor of +30 Saybolt, must pass the UV Absorption Test (ASTM D-2008) andthe USP Hot Acid Test (ASTM D-565 Nonetheless, it is a primary objectiveof the present invention to obviate these and other prior artdifficulties and, in particular, to provide a new and improved process,or process combination, for manufacture of white oils which willeliminate any necessity of acid treating.

A further object is to provide a process for manufacturing highly stablewhite oils from raw distillates and semi-refined oils in good yieldcontaining very insignificant concentrations, if any, of sulfur,nitrogen, oxygen and aromatics.

A specific object is to provide a process combination including asequence of steps for manufacturing semi-refined oils, and subsequenttreatment of such oils in the presence of highly active complexcatalysts, at suitable conditions, for essentially complete saturationof the aromatics to produce white oils in good yield.

These and other objects are achieved in accordance with the presentinvention which provides a process comprising treating petroleum oils ofsuitable boiling range and viscosity, including raw distillates andsemi-refined oils, and refining the latter to white oil specificationsby hydrogenation with highly active supported transition metal complexcatalysts, at hydrogenation conditions. The catalyst complex is formedby depositing a transition metal salt from solution on a suitablesupport material and activating the salt with a liquid-solubleorgano-metallic compound.

Raw distillates and semi-refined oils of suitable boiling range andviscosity, provide feedstocks suitable for use in the preparation ofwhite oils by contact with the highly active complex catalysts, athydrogenation conditions. The feedstocks can be obtained by conventionalprocessing comprising (a) solvent extracting a lubricating oil or rawdistillate to obtain a rafi'mate; (b) treating the raffinate withhydrogen over an active hydrodesulfurization catalyst at conditionssuitable to reduce the sulfur content, and then (c) distilling thehydrotreated product under vacuum to remove overhead a low boilingfraction, while recovering a higher boiling, semirefined low sulfur oilfraction. Suitably, e.g., a petroleum oil, obtained by distillation,boiling in the range of 400 to l,025 F. and having a viscosity of about35 to 2,500 SSU at l F. can be extracted with a suitable solvent foraromatic hydrocarbons, e.g., phenol, furfural or S0: to produce araffinate boiling in the range of about 400 to l,025 F. The raffinatecan be hydrogenated, if desired, or necessary, with a conventionalhydrodesulfurization catalyst to produce a low sulfur oil containing,preferably, less than about 5 ppm sulfur. This oil, or feedstock, canthen be upgraded to specification white oil by a second hydrogenation inthe presence of a highly active catalyst complex formed bya supportedtransition metal salt, activated with a liquid-soluble organo-metalliccompound.

Suitable feedstocks for conversion to white oils over the highly activecomplex catalysts are those boiling within'a range of from about 400 tol,025 F., a higher, preferably from about 650 F. to l,025 F. Whilehigher boiling feedstocks can be used, this is not generally desirableinasmuch as process conditions must be increased in severity to animpractical extent. Viscosities range preferably from about 30 to about2,500 SSU at F., and more preferably from about 35 to 500 SSU at 100 F.,but viscosity can be readily controlled, e.g., by topping. The aromaticscontent of the initially treated feed is not critical inasmuch asaromatics can be reduced to an acceptable level by extraction andprehydrogenation, but the aromatics content of the feedstock directlyused for treatment and hydrogenation with the complex catalyst shouldpreferably be no greater than about 5 percent, based on the weight ofthe feedstock, and is more preferably less.

Conventional solvent extraction processes can be used to reduce thearomatic hydrocarbon content of the oil. For example, a preferredextraction with phenol at a temperature in the range of 100 to 300 F.and a pressure in the range of about ambient to l00 psig provides asuitable means of aromatics removal. Suitably, from about 50 to 500percent of the solvent, based on the weight of the oil, is employed inthe extraction.

The raffinate is hydrogenated at relatively severe conditions to removetheheterocyclic compounds, and in particular to reduce the sulfurcontent of the oil, preferably to less than about 5 ppm sulfur. Suitablehydrogenation conditions include temperatures in the range of about 400to 800 F., and preferably in the range of about 600 to 700 F.; pressuresin the range of about l,000 to 10,000 and preferably in the range ofabout 500 to 5,000 psig; space velocities in the range'of about 0.1 to10 VIl-lrJV, preferably in the range of about 0.1 to 2 V/Hr./V; andhydrogen rates of from about 500 to 10,000 SCF/Bbl. and preferablyhydrogen rates of about l,000 to 5,000 SCF/Bbl. of feed. Suitablehydrotreating catalysts comprise one or more hydrogenation metalssupported on a suitable carrier material. The metals are in the form ofmetal oxides or metal sulfides. Salts of Group VI and Group VIII metalsare the preferred hydrogenating components. Specifically, oxides orsulfides of molybdenum, tungsten, cobalt, nickel and iron are used.Alumina, alumina containing 1 to 10 weight percent silica, bauxite,kieselguhr, etc., are preferred support materials. The most preferredcatalysts are sulfided cobalt molybdate or sulfided nickel molybdate onalumina or silica alumina. The catalyst can be disposed for contactingin a fixed bed for liquid phase or mixed phase contacting. This firststage of hydrogenation performs several functions, includinghydrodesulfurization, hydrodenitrogenation, saturation of olefins, somesaturation of aromatic hydrocarbon rings, etc. The hydrofined, orsemi-refined, oils can be topped, if desired, to adjust viscosity andspecific gravity in accordance with market requirements.

The feedstocks, or white oil base stocks, can be hydrogenated in thepresence of the high activity complex catalysts to produce white oils.Pressures, space velocities and hydrogen rates are essentially the sameas in the first hydrogenation stage wherein salts of Groups VIB and VIIIhydrogenation metals are employed,,though temperatures are generallylower. Preferably, the temperature employed in hydrogenation of thefeedstocks with the highly active complex catalysts ranges from about350 to 600 F., and more preferably from about 475 to 525 F. The highlyactive complex catalysts are prepared by the steps of impregnating asupport with a solution of a liquid soluble compound of a transitionmetal, preferably a Group VIII metal of the Periodic Chart of theElements; and then activating the supported metal species with asolution of an organo-metallic compound, a metallic constituent of whichis selected from Groups I, II and III of the Periodic Chart of theelements. The transition or Group VIII metal salt can be dissolved in anaqueous or nonaqueous medium to form the solution, depending on thespecificnature and characterof the salt. Preferably, a watersoluble fonnof salt is used, and in impregnation of the support, subsequentactivation steps include: heat-treating the impregnated supportsufficient to form a complex of a species of the metal at the surface ofthe support and to remove liquid and adsorbed oxygen; activating thesupported metal complex by contacting same with a liquid solubleorgano-metallic compound, a metallic constituent of which is selectedfrom Groups I, ll and Ill of the Periodic Chart of the Elements, andtreating the activated supported metal complex to eliminate volatilematter.

- A highly te naceous chemical bonding can be formed between the surfaceof certain types of supports and transition or Group VIII metals,particularly iron, cobalt and nickel, of the Periodic Chart of theElements, when the latter are applied to the supports as solutions ofthe desired metal, and heat treated. The supported species, or productformed by the heat treatment, is further chemically altered andactivated by treatment with liquid soluble organometallic compounds,wherein the metal constituent of the compound is selected from Groups I,II and III of the Periodic Chart of the Elements.

Various solvents are suitable for dissolving metal salts, includingwater which is particularly suitable for application of the transitionor Group VIII metal salt to the support. In the sequence of processsteps, in any event, a support is first impregnated with asolvent-soluble or water-soluble species of a transition or Group VIIImetal salt, preferably iron, cobalt, and nickel, by contact or immersionof the support in an organic or aqueous solution of a salt of thedesired metal. Suitably, the support is impregnated with from about 1 toabout 20 percent metal, and preferably from about 2 to about l percentmetal, based on the total weight of the deposited metal and support.

The use of water to effect the chemical bonding is particularlyimportant in the impregnation of the supports with the water-solublesalts of the desired Group VIII metal. Even iron has produced anexceptionally active catalyst when applied to the support in the form ofsalts dissolved in'aqueous solution. Exemplary of water-soluble saltsuseful for application of the desired metals are halides, e.g., ferricchloride, ferrous chloride, cobaltous chloride, nickel chloride, nickelbromide, nickel fluoride, sulfates, e.g., ferric sulfate, ferrousammonium sulfate, nickel sulfate, cobaltous sulfate, nitrates, e.g.,cobaltous nitrate, nickel nitrate, ferric nitrate, water-solublecarboxylic acid salts, e.g., cobaltous acetate, nickel acetate, ferricor ferrous acetates, formates, propionates, and water-soluble phosphatesand the like. Exemplary of salts useful for application by solution inorganic solvents, e.g., petroleum naphthas, alcohols, ethers, ketonesand the like are the acetyl acetonates, carbonates, halides, chelates,and various heterocyclic compounds of iron, cobalt and nickel.

Where the support, in powder or granular form, is impregnated with anaqueous salt solution it is next treated by establishingtime-temperature relationships suitable to produce a chemical change onthe surface of the support and to remove water and adsorbed oxygen.Suitably, the impregnated support can be heated in air, in inertatmosphere or in vacuum, e.g., 20 to 29 inches of mercury, at from about300 to about l,200 F., or preferably from about 400 to about 800 F., forperiods ranging from about 0.5 to about 4 hours, or preferably fromabout 1 to about 2 hours. On the other hand, the reaction between thesalt and support can be accomplished by the elevated temperatures whilemoisture is stripped from the support with nitrogen, or othernonreactive gas. If desirable, the impregnation and heat-treating stepscan be conducted in multiple stages. For example, the support can beimpregnated and thence dried, or partially dried, at low temperature.The support can thence be reimpregnated and again dried, or partiallydried. The heat treatment per so can also be conducted in multiplestages, if desired. The impregnated support, to facilitate handling, canthus be subjected to a first rather mild heat treatment to dry thesupport and thence, in a second step, to a more severe treatment toproduce the desired chemical change at the surface. In the formation ofsuch catalysts, supported catalysts such as supplied by commercialcatalyst manufacturers, e.g., iron, cobaltor nickel, alone or incombination with other metals such as molybdenum, tungsten or the like,are also amenable to such treatments to transfonn them into highlyactive catalysts.

Suitable supports are the oxides of Group II, III, IV, V and VIB of thePeriodic Chart of the Elements, though the oxides of Groups II, IIIA andIVB are preferred. The Group lllA metal oxides, particularly boria andalumina, are especially preferred. Alumina supports, in fact, are quiteoutstanding from a cost-effectiveness standpoint and are readilyavailable. Silica-free alumina has been found especially suitable thoughsilica alumina combinations of types used for cracking catalysts arealso highly active. Group II metal oxides, such as zinc oxide, magnesiumoxide, calcium oxide, strontium oxide and barium oxide and also theGroup IV metal oxides, e.g., titanium oxide and zirconium oxide, Group Vmetal oxides, e.g., vanadium oxide, and activated carbon and coke areeffective. Certain natural clays, diatomaceous earths, e.g., kieselguhr,and other supports are also useful.

The impregnated support is activated by treatment with anorgano-metallic compound, suitably a hydrocarbon solution of anorgano-metallic compound, ametallic constituent of which is selectedfrom Group I, II and III, or more preferably from Group IA, IIB, and111A of atomic number ranging from 3 to 30, of the Periodic Chart of theElements. Suitably, compounds include those having the formula: M(R,,)Xwherein M is a Group I, II, or III, and preferably a Group IA, 118 or"M, metal having an atomic number of from 3 to 30, R is hydrogen or amonovalent organo or hydrocarbon radical, preferably ethyl,'propyl,isopropyl, butyl, isobutyl, cyclopentyl, cyclohexyl, phenyl, naphthyl,and benzyl; X is selected from the group consisting of halogen, R, whereR is a hydrocarbon radical as previously described for R, and OR,; and nis an integer ranging from 1 to 2. The R (and R groups can be the sameor different, substituted or unsubstituted, saturated or unsaturated,and can be alkyl, aryl, alkaryl, aralkyl, or cycloalkyl. Such groupsinclude, for example, methyl, ethyl, n-propyl, isopropyl, isobutyl,sec-butyl, tert-butyl, n-amyl, isoamyl, heptyl, n-octyl, n-dodecyl, andthe like; 2-butenyl, 2-methyl-2-butenyl and the like;cyclopentyl-methyl, cyclohexylethyl, cyclohexylpropyl and the like;2-phenylethyl, Z-phenylpropyl, Z-naphthylethyl, methyl naphthylethyl andthe like; cyclopentyl, cyclohexyl, 2,2,l'bicyclohe ptyl and the like;methylcyclohexyl, dimethylcyclohexyl, S-cyclopentadienyl, and the like;phenylcyclopentyl, and the like; phenyl, tolyl, xylyl, ethylphenyl,xenyl, naphthyl, ,cyclohexylphenyl and the like. In generaLand R groupcan contain up to about 20 carbon atoms. M is selected from such metalsas lithium, magnesium, calcium, strontium, zinc, cadmium, boron andaluminum.

Preferred activating agents are the AIR, or tri-alkyl substitutedproducts of aluminum, particularly those containing alkyl groups havingfrom one to about 12 carbon atoms, and more particularly thosecontaining from one to about four carbon atoms, especially linear alkylgroups. Exemplary of such compounds, which contain up to about 36 carbonatoms in the molecule, are trimethyl aluminum, triethyl aluminum,tri-nbutyl aluminum, tri-n-hexyl aluminum, tridodecyl aluminum and thelike. 7

The activation can be carried out with pure or diluted metal alkylcompounds in liquid or in the vapor phase. Hydrocarbon diluents of theparafiinic, cycloparafiinic or aromatic types are entirely suitable andthe metal alkyl compound may be present in concentrations of 5 percentto 50 percent in the diluent. A solution of about 20 percent aluminumtriethyl in a paraffinic diluent is a preferred activation system. Theactivation reaction is quite exothermic and it may be desirable toremove the heat of activation. The temperature during the activationstep is maintained in the range of from about 60 to about 500 F.,preferably from about 100 to about 200 F. The molar ratio of complexingagent (in terms of, e.g., the aluminum to the transition or Group VIIImetal) ranges from about 1:1 to about :1. Considerable gas liberationoccurs during activation and these gases are normally vented from thesystem. The activation is allowed to proceed until reaction is no longerobserved, generally 0.5 hour to 2 hours in contact with at least someexcess of metal alkyl compound.

After the activation step, the excess liquid can be drained from thecatalyst, if desired. In any event, it is necessary to remove theunreacted organo-metallic activating agent, unbound byproducts andvolatiles from the catalyst. This can be done by any suitable methodsuch as by washing, drying or the like, but preferably the activatedcatalyst is subjected to heattreatment at temperatures sufficient tothoroughly dry and condition the catalyst. A heat treatment is necessaryfor activation. Preferably, the heat treatment is conducted in anonreactive or hydrogen atmosphere at temperatures ranging from about250 to about 800 F., and more preferably from about 200 to about 500 F.,for periods ranging up to 24 hours, and preferably from about 0.5 toabout 4 hours, or more preferably from about 1 to about 2 hours.Complete or partial vacuum may also be used to aid in removal of excesssolvent and organo-metallic alkyl compounds.

The exact nature of the complex formed in the activation step is notknown, but it is believed that this step produces a metal-to-metal bondbetween the metal species of the salt and the metal species of which thesupport is formed. For example, in activation of a nickel saltimpregnated upon an alumina support it is believed that the nickelbecomes bonded to active sites on the support, probably to aluminum. Thetransition or Group VIII metal species, therefore, becomes highlydispersed in atomic form rather than in bulk crystallite form as inconventional catalysts, producing a highly active and stablehydrogenation catalyst.

The following examples demonstrate the more salient features and providea better understanding of the invention. In the examples immediatelyfollowing, a commercial type nickel catalyst is employed inhydrogenation of the feedstock, or white oil base stock, because ofits-known high activity and these results are compared pari passu withthe process of this invention under similar conditions, with a similarcatalyst except that the catalyst is activated with a preferred speciesof organometallic.

The examples immediately following first illustrate a 'method ofpreparing complexed transition or Group VIII metal catalysts.

EXAMPLE 1 Approximately 39 g. of nickel acetylacetonate is dissolved in350 cc. of hot toluene. 75 g. of 12-20 mesh activated alumina is addedto the solution. The solvent is evaporated by heating. 86.5 cc. oftriisobutyl aluminum in 260 cc. of n-heptane is added to the nickelimpregnated support. The aluminum-to-nickel atomic ratio is 2.511. Thenickel complex is heated in a hydrogen stream at 600 F. to remove thesolvent and yield a catalyst containing about 10 weight percent nickel.

EXAMPLE 2 The catalysts of Examples 1 and 2 are tested comparatively inthe same reactor. The feedstocks, or white oil base stocks, arenonsolvent extracted naphthenic lubricating oil distillates previouslyhydrodesulfurized at 700 F. and 1500 psigin the presence of cobaltmolybdate catalyst to reduce the sulfur content of the oil to less than2 parts per million. The conditions for the hydrofinishing treatment are500 F., 2000 psig, 0.25 V/Hr./V and 3,000 SCF/Bbl. hydrogen.

Four tests, quite rigorous in their nature, are used to assess theextent of hydrogenation of the white oil feedstock. These are:

a. Saybolt color;

b. percent of aromatics, as determined by liquid chromatography onsilica gel adsorbent; c. UV absorption coefficient of the oil at 270-278My. ex-

pressed as Log Io/I concentration X path length 7 see Haenne et al.,Journal of the O.A.O.C., Vol. 43, No. 1, pp. 92-95 (1960), on UVabsorption as measured by ASTM D-2008 and ASTM D-2269; and

d. the test for carbonizable substances, ASTM D-565, also known as theHot Acid Test.

The test results are shown in Table I which describe the successfulpreparation of technical grade white oils when using the process of thisinvention.

Table I thus shows the results obtained with the two catalysts for a lowviscosity feedstock (Feed A, having a viscosity at F. of 75 SSU). Therather insensitive test with silica gel chromatography shows that theproducts from hydrogenation with both catalysts contains essentially noaromatics. The more sensitive UV absorption and Hot Acid Tests, whichare necessary to reveal the very low aromatics content to determinewhether or not the products can meet the rigid high quality standardsrequired of white oils, however, show that the nickel complex provides aproduct which contains considerably smaller traces of aromatics than theproduct obtained when using the conventional reduced nickel catalyst.The difference is profound, and quite significant for products intendedfor use as white oils.

*Tag Robinson.

The same comparative test is carried out on a semirefined high viscositynaphthenic lubricating oil feed (Feed B) having a viscosity at 100 F. of478 SSU. The test results are shown in Table II.

All four tests demonstrate, as shown by reference to Table II, thesuperiority of the nickel complex catalyst in providing high puritytechnical grade white oils. Thus the process of the invention providesan effective means for producing specification grade white oils.

The following example further demonstrates that even products meetingspecifications for pharmaceutical-grade white oils can be made pursuantto the practice of this invention.

EXAMPLE 3 In Table Ill, data are again given comparing the process ofthis invention using a complex nickel catalyst vis-a-vis a commerciallyavailable nickel catalyst. The example also shows a preferred processingsequence of steps involving solvent extraction to produce a higher gradeof semi-refined feed.

A Tia Juana heavy grade distillate (850-l,050 F; 60.6-71.9 percent yieldon crude) is prepared, and phenol-extracted to produce a raftinate in40-45 percent yield, based on the weight of the distillate. Therafiinate is hydrodesulfurized over a 5/ 25 cobalt molybdate catalyst at1,500 psig, 700 F. and 0.25 V/V/Hr. and then topped to 800 F at 80.percent yield, to provide a semirefined oil.

EXAMPLES 4-6 A Tia Juana light grade oil, 675-800 F. distillate, 45l-52.4 percent, based on the weight of crude, is phenol-extracted andsubjected to hydrodesulfurization as in the foregoing example, and thentopped to 600 F., at 95 percent yield. This feedstock, or white oil basestock, is then hydrogenated with aluminum alkyl reduced metal catalystsat 2,000 psig, 500 F. and 0.36 LHSV prepared as follows: 7

A. One hundred grams of aqueous solution is preparedv by dissolving 34grams FeCl 6H,O in 66 grams of water. One hundred grams F-l alumina (8-l4 mesh) is added to the solution and allowed to stand with occasionalmixing for about minutes. A small quantity of liquid is poured off andthe TABLE II Catalyst Nickel complex Commercial Feed B reduced nickelTemperature, F 500 500 Pressure, p.s.i.g 2, 000 2, 000 Space velocity,LHSV 0. 25 0. 25 Hz Throughput, s.c.t./bbl 3, 000 3, 000 No. Passes 1 21 2 Inspections:

Viscosity at 100 F., SSU 478 450 439 462 453 Color, Saybolt +29 +24 +28Aromatics, weight percent 28. l 1. 6 Nil 11. 4 5. 3 UV Absorption270-278 mp, 1./g.

c111 1. 045 0. 014 0. 0087 0. 502 i 0. 084 Carboniznble substances, ASTMI)565, Color N o Black Brown 20 Black Black Tag Robinson.

The semirefined oil is then hydrogenated at 2,000 psig, 500 F 0.25V/V/l-lr., and 2,000 SCF/Bbl. first over the commercial catalyst asdefined in Example 2, and then over the alkyl activated catalyst definedin Example 1. The results are tabulated in Table lll.

TABLE [I] Hydrogenation Conditions: 2,000 psig, 500F.,

0.25 V/V/Hr., 2,000 SCF/Bbl. Commercial Reduced Complex Re- NickelNickel quire- Catalyst Catalyst merits U.S.P. hot acid 3-4 1 Spec.: 3max. ASTM D-565 U.V. absorbance ASTM D-2008 275 mu 0.l72 0.041 Spec.:0.3

max. 2959 mu 0.230 0.066 Spec.: 0.225

max. 300-400 m 0.220 0.066 Spec.: 0.18

max. DMSO-UV absorbance ASTM D-2269 260-350 my. 0.03 0.040 Spec.: 0.10

max. Odor and taste Did not pass Pass Overall yield, based on theinitial distillate, is 31 percent. It is thus seen by comparison of theabove data that the process utilizing the catalyst of this inventionreadily produces finished pharmaceutical grade white oil, in good yield,whereas the process employing the commercial nickel catalyst cannot,even though the same optimum operating conditions are employed.

catalyst freed of excess liquid by placing on absorbent paper towels.The catalyst is dried for 3 hours in a vacuum oven at 475550 F. Therecovered catalyst weighs l07.4 grams, and analyzes 5.3 percent iron(calculated as Fe).

A heated quartz reaction tube is charged with 25.7 grams of the abovecatalyst and a preheat area above the catalyst bed is filled withstainless steel distillation packing. The catalyst is heated in a streamof dry nitrogen at a temperature of 500-55 0 F. for one hour and is thencooled in nitrogen to room temperature. The reactor is flooded from thebottom with a 20 percent solution of aluminum triethyl. Considerable gasis evolved and the maximum temperature reached is 200 F. After 1.33hours, the solution is withdrawn. A rapid flow of nitrogen is introducedand the temperature is increased to 350 F. Stripping is continued forabout 30 minutes.

B. A commercial cobalt molybdena-on-alumina catalyst (Nalco 471A)containing about 3.5 percent C00 and 12 percent MoO and in the form ofl/16-inch extruded rods calcined at l,200 F. for 12 hours and thencharged (36.7 grams) to the quartz reaction tube is heated in a flow ofdry nitrogen. After cooling in dry nitrogen, the catalyst bed is floodedwith 20 percent aluminum triethyl. Maximum temperature reached is F.After 40 minutes, the solution is withdrawn and the catalyst brought to600 F. in a stream of dry hydrogen. Substantially all volatile materialis removed in 15 minutes at 500 F.

C. One hundred grams of F-l alumina is slurried with 200 ml. water withmechanical agitation. Over a period of 5 minutes, 20 m]. platinumchloride-l-lCl solution (0.56 gm. Pt) is added and agitation continuedfor 30 minutes. Liquid is decanted off and the catalyst is dried in avacuum oven at F. The catalyst analyzes 0.13 weight percent platinum.

The quartz tube is charged with 48.2 gms. of the above catalyst and thecatalyst is heated in a stream of dry nitrogen at 600 F. for l hour.After cooling to room temperature, the catalyst is treated with 20percent AlEt (heptane) solution for a period of 90 minutes during whichthe maximum temperature noted is 215 F.

After draining off the liquid, the catalyst is treated in a flow of dryhydrogen at 400 F. for 1 hour.

In each instance it is found that a suitable technical grade white oilis prepared.

We claim:

1. A process for producing a white oil comprising contacting a lowsulfur content white oil base stock boiling within a range of from about400 to about l,025 F. and having a viscosity ranging from about 35 toabout 2,500 SSU at 100 F. at hydrogenation conditions with hydrogen anda catalyst comprising a complex of a metal selected from the groupconsisting of iron, cobalt and nickel composited with a support selectedfrom the group consisting of alumina, silica-alumina and boria, saidcatalyst having been prepared by reacting a composite of a salt of thesaid metal and said support with an aluminum compound having the generalformula AlR in which R is an alkyl, aryl, alkaryl, aralkyl or cycloalkylradical and heating in a non-reactive atmosphere to activate the saidcatalyst.

2. The process of claim 1 wherein the sulfur content of the white oilbase stock is less than about 5 ppm.

3. The process of claim 1 wherein the boiling range of the white oilbase stock ranges from about 650 to about l,025 F.

4. The process of claim 1 wherein the catalyst composite comprises ofnickel on alumina.

5. The process of claim 1 wherein the viscosity of the white oil basestock ranges from about 35 to 50 0 SSU at 100 F.

6. A process for producing white oil from a petroleum lubricating oilfraction containing contaminants including aromatic hydrocarbons, sulfurcompounds nitrogen compounds comprising the steps of:

a. contacting said fraction at a temperature in the range of about 400to 800 F. and a pressure in the range of about 500 to 5,000 psig withhydrogen and a first catalyst comprising a support material and ahydrogenation component selected from the group consisting of Group VI-Bmetals, Group Vlll metals and mixtures thereof;

b. recovering a semi-refined fraction having a substantially reducedquantity of said contaminants; and

c. contacting said semi-refined fraction at relatively mildhydrogenation conditions with hydrogen and a second catalyst comprisingcomplexed metal on alumina, said metal being selected from the groupconsisting of iron, cobalt and nickel, and said second catalyst havingbeen complexed by reacting said metal on alumina with an aluminumcompound having the general formula AlR in which R is an alkyl, aryl,alkaryl, aralkyl or cycloalkyl radical.

7. The process of claim 6 wherein the said second catalyst comprisescomplexed nickel on alumina, said catalyst having been prepared byreacting a nickel on alumina composite with the said aluminum compound.

8. A process for producing a white oil consisting essentially of thesteps of:

a. extracting a naphthenic lubricating oil fraction with a solvent toremove aromatics;

b. recovering a raffinate fraction comprising a to 75 volume percent ofsaid lubricating oil fraction;

c. contacting said raffinate with hydrogen at a temperature in the rangeof 600 to 800 F. and a pressure in the range of 1,000 to 10,000 psig inthe presence of a catalyst comprising a support material and ahydrogenation component selected from the group consisting of Group Vl-Bmetals, Group VIII metals and mixtures thereof;

. recovering a semi-refined white oil;

. distilling the semi-refined white oil to obtain a topped fractionhaving a viscosity in the range of 30 to 2,500 SSU at 100 F.;

. contacting said topped fraction with hydrogen at a temperature in therange of 475 to 525 F. and a pressure in the range of 1,000 to 10,000psig, and with a catalyst composite comprising a supported complex metalcatalyst, said catalyst having been prepared by impregnating a supportselected from the group consisting of alumina, silica-alumina and boria,with a salt of a metal selected from the group consisting of iron,cobalt and nickel, heating said impregnated support to form saidsupported complex metal catalyst, reacting said supported catalyst withan aluminum compound having the general formula A 111;, in which R is analkyl, aryl, alkaryl, aralkyl or cycloalkyl radical, and heating in anon-reactive atmosphere to activate the said catalyst; and

g. recovering a white oil which passes the Hot Acid Test.

9. The process of claim 8 wherein the solvent is phenol.

10. The process of claim 8 wherein the catalyst contacted by therafiinate in step (c) comprises a sulfided cobalt molybdate on alumina.

11. The process of claim 8 wherein the supported complex metal catalystis nickel on alumina.

12. The process of claim 8 wherein the topped semi-refined white oil isone having a viscosity ranging from about 30 to about 500 SSU at 100 F.

13. A process for processing white oil comprising forming a white oilbase stock by at extracting an oil boiling in a range of from about 400to about l,025 F., and having a viscosity of about 35 to about 2,500 SSUatl00 F. with a solvent to produce a raffinate of reduced aromaticcontent, said raft'mate boiling within the range of from about 400 toabout 1,025" F.,

hydrodesulfurizing the raffinate by contact with a hydrogenationcatalyst comprising a support material and a hydrogenation componentselected from the group consisting of Group Vl-B metals, Group VIIImetals and mixtures thereof, at a temperature ranging from about 400 to800 F., a pressure ranging from about 1,000 to 10,000 psig, spacevelocities ranging from about 0.1 to 10 Vll-lr./V, and at hydrogen ratesof from about 500 to 10,000 SCF/Bbl contacting said desulfurized oil athydrogenation conditions with hydrogen and a catalyst compositecomprising support selected from the group consisting of alumina,silicaalumina and boria, and a metal selected from the group consistingof iron, cobalt and nickel, said catalyst composite having been preparedby reacting the said composite with an aluminum compound having thegeneral formula AIR in which R is an alkyl, aryl, alkaryl, aralkyl orcycloalkyl radical and recovering a colorless white oil containingessentially no aromatic compounds.

2. The process of claim 1 wherein the sulfur content of the white oilbase stock is less than about 5 ppm.
 3. The process of claim 1 whereinthe boiling range of the white oil base stock ranges from about 650* toabout 1,025* F.
 4. The process of claim 1 wherein the catalyst compositecomprises of nickel on alumina.
 5. The process of claim 1 wherein theviscosity of the white oil base stock ranges from about 35 to 500 SSU at100* F.
 6. A process for producing white oil from a petroleumlubricating oil fraction containing contaminants including aromatichydrocarbons, sulfur compounds nitrogen compounds comprising the stepsof: a. contacting said fraction at a temperature in the range of about400* to 800* F. and a pressure in the range of about 500 to 5,000 psigwith hydrogen and a first catalyst comprising a support material and ahydrogenation component selected from the group consisting of Group VI-Bmetals, Group VIII metals and mixtures thereof; b. recovering asemi-refined fraction having a substantially reduced quantity of saidcontaminants; and c. contacting said semi-refined fraction at relativelymild hydrogenation conditions with hydrogen and a second catalystcomprising complexed metal on alumina, said metal being selected fromthe group consisting of iron, cobalt and nickel, and said secondcatalyst having been complexed by reacting said metal on alumina with analuminum compound having the general formula A1R3 in which R is analkyl, aryl, alkaryl, aralkyl or cycloalkyl radical.
 7. The process ofclaim 6 wherein the said second catalyst comprises complexed nickel onalumina, said catalyst having been prepared by reacting a nickel onalumina composite with the said aluminum compound.
 8. A process forproducing a white oil consisting essentially of the steps of: a.extracting a naphthenic lubricating oil fraction with a solvent toremove aromatics; b. recovering a raffinate fraction comprising a 30 to75 volume percent of said lubricating oil fraction; c. contacting saidraffinate with hydrogen at a temperature in the range of 600* to 800* F.and a pressure in the range of 1, 000 to 10,000 psig in the presence ofa catalyst comprising a support material and a hydrogenation compoNentselected from the group consisting of Group VI-B metals, Group VIIImetals and mixtures thereof;; d. recovering a semi-refined white oil; e.distilling the semi-refined white oil to obtain a topped fraction havinga viscosity in the range of 30 to 2,500 SSU at 100* F.; f. contactingsaid topped fraction with hydrogen at a temperature in the range of 475*to 525* F. and a pressure in the range of 1,000 to 10,000 psig, and witha catalyst composite comprising a supported complex metal catalyst, saidcatalyst having been prepared by impregnating a support selected fromthe group consisting of alumina, silica-alumina and boria, with a saltof a metal selected from the group consisting of iron, cobalt andnickel, heating said impregnated support to form said supported complexmetal catalyst, reacting said supported catalyst with an aluminumcompound having the general formula A1R3 in which R is an alkyl, aryl,alkaryl, aralkyl or cycloalkyl radical, and heating in a non-reactiveatmosphere to activate the said catalyst; and g. recovering a white oilwhich passes the Hot Acid Test.
 9. The process of claim 8 wherein thesolvent is phenol.
 10. The process of claim 8 wherein the catalystcontacted by the raffinate in step (c) comprises a sulfided cobaltmolybdate on alumina.
 11. The process of claim 8 wherein the supportedcomplex metal catalyst is nickel on alumina.
 12. The process of claim 8wherein the topped semi-refined white oil is one having a viscosityranging from about 30 to about 500 SSU at 100* F.
 13. A process forprocessing white oil comprising forming a white oil base stock by atextracting an oil boiling in a range of from about 400 to about 1,025*F., and having a viscosity of about 35 to about 2,500 SSU at100* F. witha solvent to produce a raffinate of reduced aromatic content, saidraffinate boiling within the range of from about 400 to about 1,025* F.,hydrodesulfurizing the raffinate by contact with a hydrogenationcatalyst comprising a support material and a hydrogenation componentselected from the group consisting of Group VI-B metals, Group VIIImetals and mixtures thereof, at a temperature ranging from about 400* to800* F., a pressure ranging from about 1,000 to 10,000 psig, spacevelocities ranging from about 0.1 to 10 V/Hr./V, and at hydrogen ratesof from about 500 to 10,000 SCF/Bb1., contacting said desulfurized oilat hydrogenation conditions with hydrogen and a catalyst compositecomprising support selected from the group consisting of alumina,silica-alumina and boria, and a metal selected from the group consistingof iron, cobalt and nickel, said catalyst composite having been preparedby reacting the said composite with an aluminum compound having thegeneral formula A1R3 in which R is an alkyl, aryl, alkaryl, aralkyl orcycloalkyl radical and recovering a colorless white oil containingessentially no aromatic compounds.